Re: Is it possible to redirect an update/insert/delete to a different table? - Mailing list pgsql-sql

From Andreas Kretschmer
Subject Re: Is it possible to redirect an update/insert/delete to a different table?
Date
Msg-id 20051120164234.GB2832@kaufbach.delug.de
Whole thread Raw
In response to Re: Is it possible to redirect an update/insert/delete to a different table?  (Andy Ballingall <andy@areyoulocal.co.uk>)
Responses Re: Is it possible to redirect an update/insert/delete to a different table?
List pgsql-sql
Andy Ballingall <andy@areyoulocal.co.uk> schrieb:

> Hello Jaime,
> 
> I'm still not quite clear.
> 
> Say I have a number of different updates on a table 'apples' in my code,
> including:
> 
> UPDATE apples set pips=6 and color='yellow' where id=3;
> UPDATE apples set size=10 where id=6;
> 
> What would a rule look like which, when *any* update is attempted on the
> apples table, will instead apply the update to a different table - 'pears'.

Try it.

test=# create table apples (id int, name1 text, name2 text);
CREATE TABLE
test=# create table pears (id int, name1 text, name2 text);
CREATE TABLE
test=# create rule apples_pears_update as on update to apples do instead
update pears set name1= NEW.name1, name2=NEW.name2 where id=NEW.id ;
CREATE RULE
test=# insert into apples values (1, 'a', 'a');
INSERT 0 1
test=# insert into pears values (1, 'a', 'a');
INSERT 0 1
test=#
test=# update apples set name1='b' where id = 1;
UPDATE 1
test=# select * from pears ;id | name1 | name2
----+-------+------- 1 | b     | a
(1 row)

test=# update apples set name2='c' where id = 1;
UPDATE 1
test=# select * from pears ;id | name1 | name2
----+-------+------- 1 | a     | c
(1 row)

test=# update apples set name1='e', name2='e' where id = 1;
UPDATE 1
test=# select * from pears ;id | name1 | name2
----+-------+------- 1 | e     | e
(1 row)



> 
> -----Original Message-----

Please, no top-posting.


HTH, Andreas
-- 
Really, I'm not out to destroy Microsoft. That will just be a completely
unintentional side effect. (Linus Torvalds)
Kaufbach, Saxony, Germany, Europe.              N 51.05082°, E 13.56889°


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